The two women have entered the ultra-distance London 2 Brighton Challenge on May 26, hoping to complete the 100km run in 18-20 hours, and raise at least £1,000 for the TTBS.
Ms Smith plays hockey and has completed two half-marathons while Ms Heardman has run 10km in the past. Setting their sights on a marathon may seem more manageable but the pair wanted a true challenge.
"We thought if we wanted to get people to dig deep to donate to the TTBS we would have to do something that required real stamina and dedication," said Ms Smith.
The two are training hard, getting to the gym at 5am for a session before work, and training again in the evening.
To make a donation to their 100km effort, go to www.justgiving.com/Becca-Smith-Harriet-Heardman
